1. Field of the Invention
The present invention generally relates to balancing equipment for multi-direction positioning apparatus, and particularly to those devices which require accurate balancing such as cameras and other optical systems.
2. Prior Art
There are numerous devices disclosed by the prior art which involve either mounting devices for equipment such as a camera, or worm gear assemblies which are described independent of any specific application. One of the devices taught by the prior art discloses a panning and tilting mount for a camera. Although the present invention is usable in applications other than those which would occur in the use of film or video cameras, for the purpose of example, these devices shall be used for descriptive use only. The devices taught by the prior art provide separate motivating force elements for the panning and tilting functions, respectively. A motor is mounted on a suitable panel and is adjustably positioned by connecting the motive force through a worm gear assembly. As the worm gear is caused to rotate, the entire motor housing is thereby rotated due to the cooperation between the worm gear and the stationary gear. One of the problems inherent in this device is created by the application itself. Since motion picture or video cameras are unsymmetrical in one or more of their three axes, it is clear that the inbalance which is caused as a result of the unsymmetrical mass could be translated into an inability to accurately position the camera. The present invention substantially resolves this problem by providing for static balancing of the camera prior to operation but without disconnecting any major subsystems. By allowing the worm gear to be disengaged from the stationary, master drive gear associated with each of the axes of rotation, the camera can be statically balanced to provide for accurate positioning control.
Other devices taught by the prior art employ worm gears which can be disengaged from a second gear with which it meshes. In these devices, the worm gear can be disengaged to permit the meshing gear to be rotated without interference from the worm gear and the coupled assembly. As an example, where the meshed gear is coupled to a drum employed to wind cable, a separate power force can rotate the drum to wind the cable after which the worm gear can be engaged to permit more accurate adjustment. The inadequacies of these devices is apparent. The worm gear is employed solely for the purpose of providing small changes in the position of the meshed gear and the equipment to which it is attached. The present invention employs the worm gear as part of the power train between the motive force used as the source of power to change the position of the camera along a given axis and the camera positioning drive gear itself. In the engaged position, the worm gear is fully meshed to the main drive gear and, through the universal joint, to the camera positioning controls. In order to balance the camera, the worm gear is disengaged thereby uncoupling the camera positioning controls from the main drive gear.
The present invention provides an improved gear apparatus for remote positioning of a camera or like device. By coupling each of the main drive gears to the positioning controls through the engageable worm gear, the camera can be statically balanced independent of any forces imposed by the main drive gears. By providing for motive force in each of the two axes of movement, substantially all static effects of the mass of the camera can be compensated for prior to operation.